drivers are part of a Casette hub. Its the ring on the out side that drives the wheel. Profile used to make these back in the day and were very exspensive but now they are cheaper and way more durable.
For flatland, I wouldnt suggest this but people still use the freecoaster "Old tech" but it works there are just to many flatland riding options out there. brakes all around, no brakes, one front brake no free coaster ect.
There are tons of options out there I havnt touched my bike since going on "Props" Mega tour last spring. I do regret getting off my bike but it was the best option for me as I'm in school now learning and hopefully graduate to earn money to survive on.
For any parts and best guys around and I used to ride for them. "I'm still family" check out www.albes.com Tell em shanton Wilson sentya. and if you mention exploding penguins while ordering the parts you get free shipping.